Audio production can involve the use of many components, including microphones, wireless audio transmitters, wireless audio receivers, recorders, and/or mixers for capturing and recording the sound of productions, such as television programs, newscasts, movies, live events, and other types of productions. The microphones typically capture the sound of the production, which is wirelessly transmitted from the microphones and/or the wireless audio transmitters to the wireless audio receivers. The wireless audio receivers can be connected to a recorder and/or a mixer for recording and/or mixing the sound by a crew member, such as a production sound mixer. Electronic devices, such as computers and smartphones, may be connected to the recorder and/or mixer to allow the crew member to monitor audio levels and timecodes.
Wireless audio transmitters, wireless audio receivers, and other portable wireless communication devices include antennas for transmitting radio frequency (RF) signals which contain digital or analog signals, such as modulated audio signals, data signals, and/or control signals. Users of portable wireless communication devices include stage performers, singers, actors, news reporters, and the like. One common type of portable wireless communication device is a wireless bodypack transmitter, which is typically secured on the body of a user with belt clips, straps, tape, etc.
The electrically small antennas included on portable wireless communication devices are typically low profile and small so that the size of the devices is reduced, physical interaction with the antennas is minimized, and to assist in concealing the devices from an audience. Antennas may extend from the device or be included within the device, depending on the type of antenna being utilized. However, the usable bandwidth and efficiency of an antenna are reduced as the size of the antenna is reduced, due to fundamental physical limitations. Furthermore, electrically small antennas are more likely to be subject to the detuning effects of being close to a human body. For example, an RF signal transmission may be degraded by 20 dB in some situations because of the proximity of a human body near an antenna.
Typical antenna types used in portable wireless communication devices include quarter wave whip antennas, partial or complete helical antennas, ceramic chip antennas, and other types of antennas. Each of these antenna types has drawbacks. A quarter wave whip antenna may extend from the device and therefore be excessively long, hard to conceal, and prone to damage. A partial or complete helical antenna may also extend from the device and have limited operating bandwidth, degraded radiation efficiency, and be prone to detuning when close to a human body. While able to be included within a device and physically smaller than the other antenna types, a ceramic chip antenna may have very low radiation efficiency, extremely limited operating bandwidth, and also be prone to detuning when close to a human body.
Accordingly, there is an opportunity for systems and methods that address these concerns. More particularly, there is an opportunity for adaptive self-tunable antenna systems and methods for tuning an antenna with a closed-loop system for enabling the antenna to have increased radiation resistance, improved radiation efficiency, maximized far field strength for improved auto-tunable operating frequency, less sensitivity to detuning, and the ability to be integrated within a device.